Experiments were performed on hearts of open chest dogs whose coronary arteries were not perturbed. We measured conventional global functions such as coronary flow, cardiac output, intravascular pressures and their derivatives, myocardial uptake of O2, lactate, pyruvate and glucose. From drill biopsies of the left ventricle we also measured regional tissue content of high energy phosphate compounds pyruvate and lactate. We have completed the study in dogs during isoproterenol infusion and found that there were no parameters that we measured or that we calculated (e.g., diastolic/systolic pressure time, or LV inner/outer flow) that would predict a reduction of tissue CP. The present proposal will involve making similar measurements in 3 types of experimental aortic stenosis; supravalvular ascending, supravalvular descending and subvalvular aortic stenosis to try and determine the effect of flow and LV work on tissue content of high energy phosphate compounds.